Arnold, Sir Nicholas (1507×1509–1580), lord justice, was second son of John Arnold of Churcham, Gloucestershire (protonotary and clerk of the crown in Wales, and holder of two manors in Gloucestershire), and his wife Isabel (née Hawkins). Nicholas entered Henry VIII's service in 1526, acting under Thomas Cromwell in the dissolution of the monasteries, as a royal bodyguard, and as a fort commander in the Boulogne defences (1546–50); he was knighted under Edward VI, but under Mary was twice imprisoned for conspiracy. In 1562, in consequence of opposition in the Pale to the exactions of the earl of Sussex (qv) in supporting an army, Arnold (protégé of Sussex's rival at court, the earl of Dudley) was sent to Ireland heading a commission to investigate charges of fiscal abuse. Its report was unfavourable, and Arnold was commissioned (October 1563) to investigate all alleged abuses of the Irish government; on Sussex's recall to England, Arnold was made lord justice (May 1564).
His administration was not a success, though the restoring of some officeholders who had been out of Sussex's favour was welcomed (particularly the earl of Kildare (qv) in the defence of the Pale). His main purpose – reducing expenditure – was resisted by officials (chiefly Sir William Fitzwilliam (qv), vice-treasurer) and army commanders. The army was indeed cut by about half, but at the cost of doing nothing about the Gaelic Irish, whom Arnold reportedly regarded as ‘bears and bandogs. So that he sees them fight earnestly, and tug each other well, he cares not who has the worse’ (CSPI, 1509–73, 252). Arnold was abrasive and unconciliatory; after a year he was reduced to suggesting that uncooperative council members should be replaced.
In mid 1565 (after failing to prevent a revived feud between the earls of Ormond (qv) and Desmond (qv)) he was recalled, and in October Sir Henry Sidney (qv) was appointed lord deputy. Charges by Sussex against Arnold were not pursued, and he spent the rest of his life in Gloucester affairs – he was an MP for the county in four reigns, and before going to Ireland had been sheriff of the county and MP for the city – and in breeding horses. He made his will 10 April 1580 and died not long after.